Theophrastus frag. 716 [Fortenbaugh] attacks the thesis that differences between musical pitches are quantitative. Most of its fire-power is directed at harmonic theory in the 'mathematical' or 'Pythagorean' style, but one short passage (lines 108 ff.) is not. Previous commentators have identified its target as Aristoxenus; but I argue that Theophrastus' account does not fit Aristoxenus' position, and that we should look for his target in the work of earlier 'empirical' theorists. After reviewing and rejecting various possibilities, I tentatively suggest that Theophrastus' conception of the empiricists' standpoint may originate in a plausible but probably mistaken interpretation of Republic 531a-b. I then argue that so far from criticizing Aristoxenus' ideas, Theophrastus' polemic make substantial use of them. Finally, I explain how this phase of his discussion returns us to the intriguing questions from which his whole anti-quantitative tirade began. [Theophrastus and Aristoxenus, p. 101]